Re:Bitwarden: Free, open-source password manager
by jillesvangurp on Wednesday January 19, 2022 @10:45AM
(#29995089)
Yes, unfortunately a lot of implementations for this break password managers. It doesn't have to be that way and there are ways to fix it. But it complicates things a bit. And it's a pattern that actually gets copied a lot by products that definitely don't do any form of SSO.
Also, a typical opendid flow or SSO would not actually require an email field at all. So splitting the screens is kind of redundant in that case. E.g. a Github signin would be done with a button click and a few redirects.
This is done because it's an easier way to support both local login and SSO(like oauth or saml). By taking the username first you can determine whether to ask them for a password or send them to a sso provider.
It doesn't have to be implemented this way but it is seen as easier.